Patches and discussion for Ensoniq VFX family

On Sat, 2009-01-17 at 01:13 +0000, John wrote:
> This sounds similar to a problem I had except, all I got was the
> \u201cbattery low\u201d warning, no sounds.  The battery voltage is compared to
> a voltage from the PSU.  So if this becomes unstable\u2026 
> 
> In my case a diode had blown on the bridge rectifier.  I believe there
> are 6 and if ones gone it might be an idea to change all 6.

I'd go along with this.  People go on about smoothing caps failing, but
I've had far more trouble from rectifier diodes failing.  If they fail
short-circuit then you may find problems with the smoothing caps too.

Get a big bag of power diodes, and replace the lot.  I use the 800V 8A
diodes which are physically very large and may need the holes in the
board drilled out a little, whatever I'm replacing them in.  Sometimes
if I'm repairing a power supply with a large 5V draw I'll use even
higher current diodes.  They'll never ever fail again.  Ever.

Gordon